The field of microfluidics has been held up as the next great advance in biological science, akin to the advances made in the electronics industry with the development of the microprocessor. In particular, the small scale, high level of accuracy and reproducibility, and ready automatability have led to expectations that this field of research will revolutionize the way work is done in research laboratories.
As with the electronics industry, incremental advances will be achieved as the operations performed by these microfluidics systems are expanded and optimized in accordance with their increasing acceptance in the scientific area. However, also as with the electronics industry, the most significant developments in this technology will likely not involve incremental advances in specific operations, but will instead revolve around advances in the technology used to fabricate these systems. In particular, some of the most significant advances in the electronics industry have come from improved methods of producing microchips, which allow substantially increased efficiency and greater functionality in a smaller area or space.
Fabrication of microfluidic systems typically involves the fabrication of grooves in the surface of a first substrate layer, which grooves will correspond to the channel network in a finished microfluidic device. A second substrate layer is overlaid and bonded to the first to seal the grooves thereby forming the channels. Apertures disposed in one of the substrates communicate with the channels and function as access ports and or reagent reservoirs for the devices. With certain exceptions, this fabrication process has been largely unimproved for some time. Commonly owned U.S. Pat. No. 5,882,465, to McReynolds, for example describes improved methods of mating and bonding the various substrate layers together in order to improve fabrication efficiency. Similarly, Published International Patent Application No. WO 98/00705 describes methods for fabricating microfluidic devices used in high throughput assay applications.
The present invention provides additional improvements in the fabrication of microfluidic devices, which improvements improve the efficiency both of the fabrication processes and operations to be performed by microfluidic devices.